Dual network mobile device radio resource management

ABSTRACT

A single chip mobile wireless device capable of receiving and transmitting over one wireless network at a time maintains registration on two wireless communication networks that each use different communication protocols in parallel. Periodically, the mobile wireless device tunes one or more receivers from a first wireless network to a second wireless network in order to listen for paging messages addressed to the mobile wireless device from the second wireless network. The first wireless network suspends allocation of radio resources to the mobile wireless device based on receipt of a suspension message from the mobile wireless device, or based on knowledge of a paging cycle for mobile wireless device in the second wireless network, or based on detection of an out of synchronization condition with the mobile wireless device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/416,286, filed Mar. 9, 2012, entitled “DUAL NETWORK MOBILE DEVICERADIO RESOURCE MANAGEMENT”, which claims the benefit of U.S. ProvisionalApplication No. 61/478,922, filed Apr. 25, 2011, entitled “DUAL NETWORKMOBILE DEVICE RADIO RESOURCE MANAGEMENT,” which are each incorporated byreference herein in their entirety for all purposes.

FIELD

The described embodiments generally relate to methods and apparatusesfor managing radio resources and connections between mobile wirelessdevices and one or more wireless networks. More particularly, thepresent embodiments describe radio resource management between a mobilewireless device that supports multiple wireless communicationtechnologies and one or more wireless networks.

BACKGROUND

Wireless networks continue to evolve as new communication technologiesdevelop and standardize. Wireless network operators can deploy newcommunication technologies in parallel with earlier generationcommunication technologies, and wireless networks can support multiplecommunication technologies simultaneously to provide smooth transitionsthrough multiple generations of mobile wireless devices. Arepresentative wireless network can include simultaneous support for theThird Generation Partnership Project (3GPP) Long Term Evolution (LTE)wireless communication protocol and the Third Generation PartnershipProject 2 (3GPP2) CDMA2000 1× (also referred to as 1×RTT or 1×) wirelesscommunication protocol. This representative “simultaneous” wirelessnetwork can support circuit switched voice connections through a firstwireless network that uses the CDMA2000 1× wireless communicationprotocol and packet switched connections (voice or data) through asecond wireless network that uses the LTE wireless communicationprotocol. The 3GPP wireless communications standards organizationdevelops mobile communication standards that include releases for GlobalSystem for Mobile Communications (GSM), General Packet Radio Service(GPRS), Universal Mobile Telecommunications System (UMTS), Long TermEvolution (LTE) and LTE Advanced standards. The 3GPP2 wirelesscommunications standards organization develops mobile communicationstandards that include CDMA2000 1×RTT and 1×EV-DO standards. While adual network mobile wireless device that includes support for bothCDMA2000 1× and LTE is described as a representative device herein, thesame teachings can be applied to other mobile wireless devices that canoperate in dual (or more generally multiple) wireless communicationtechnology networks.

Dual chip mobile wireless devices can include separate signal processingchips that each can support a different wireless communication protocol,such as one signal processing chip for the CDMA2000 1× wireless networkand another signal processing chip for the LTE wireless network. Inparticular, in a dual chip mobile wireless device, each signalprocessing chip can include its own receive signal processing chain,including in some instances multiple receive antennas and attendantsignal processing blocks for each signal processing chip. With separatereceive antennas available to each signal processing chip in the dualchip mobile wireless device, pages can be received independently fromtwo different wireless networks, such as from the CDMA2000 1× wirelessnetwork and from the LTE wireless network, by the dual chip mobilewireless device. Even when the dual chip mobile wireless device isconnected and actively transferring data through one of the signalprocessing chips to one of the wireless networks, such as the LTEwireless network, the dual chip mobile wireless device can also listenfor and receive a paging message through the other parallel signalprocessing chip from a second wireless network, such as the CDMA2000 1×wireless network. Thus, the dual chip mobile wireless device canestablish a device originating or device terminated circuit switchedvoice connection through the CDMA2000 1× wireless network while alsobeing actively connected to (or simultaneously camped on) the packetswitched LTE wireless network. Dual chip mobile wireless devices,however, can consume more power, can require a larger physical formfactor and can require additional components (and cost more) than a moreintegrated “single chip” mobile wireless device.

A single chip mobile wireless device, at least in some configurations,can include a signal processing chip that can support different wirelesscommunications protocols but can be unable to be actively connected toone wireless network and to receive communication from a separatewireless network simultaneously. The single chip mobile wireless devicecan support multiple wireless communication technologies, such asconnections to a CDMA2000 1× wireless network or to an LTE wirelessnetwork, but only to one wireless network at any given time. The singlechip mobile wireless device can be limited to receiving signals that useone wireless communication technology type at a time, particularly whenmultiple antennas are used to receive signals for a single communicationtechnology using receive diversity. In a representative embodiment, asingle chip mobile wireless device can be able to connect to or camp onan evolved Universal Mobile Telecommunications System (UMTS) TerrestrialRadio Access Network (eUTRAN) of the LTE wireless network and also toconnect to or camp on a radio access network (RAN) of the CDMA2000 1×wireless network, but not to both wireless networks simultaneously. Thesingle chip mobile wireless device can be registered on both the LTEwireless network and on the CDMA2000 1× wireless network and cantherefore form connections with each wireless network singly but notsimultaneously. When the LTE wireless network does not support a circuitswitched fall back (CSFB) mode or voice over LTE connections, the singlechip mobile wireless device can be unable to receive a page from theCDMA2000 1× wireless network when connected to or camped on the eUTRANof the LTE wireless network. Thus, there exists a need for a methodwhereby a single chip mobile wireless device can achieve similarfunctionality to a dual chip mobile wireless device, so that the singlechip mobile wireless device can retain the ability to complete a circuitswitched voice connection through the CDMA2000 1× wireless network whenconnected to or camped on the eUTRAN of a parallel LTE wireless network.

This application describes methods by which a single chip mobilewireless device can operate in a multiple network environment supportingconnections to both an LTE wireless network and a CDMA2000 1× wirelessnetwork while optimizing radio network resources and minimizing radionetwork signaling requirements.

SUMMARY

Broadly speaking, the described embodiments relate to managing radioresources and connections between mobile wireless devices and one ormore wireless networks. More specifically, methods, apparatus andcomputer readable media are described that manage use of radio networkresources while minimizing radio network signaling requirements for asingle chip mobile wireless device that can operate in a multiplenetwork environment.

In an embodiment, a method to manage radio resources between a mobilewireless device and a first wireless network is described. The methodincludes at least the following steps executed by the mobile wirelessdevice when the mobile wireless device is associated with the firstwireless network through an established radio resource controlconnection and is simultaneously registered with a second wirelessnetwork. The mobile wireless device transmits a radio resourcesuspension trigger to the first wireless network while maintaining theestablished radio resource control connection. After transmitting theradio resource suspension trigger, the mobile wireless device tunes oneor more receivers in the mobile wireless device to listen for a pagingmessage from the second wireless network during a paging interval. Whenreceiving a paging message that includes a page addressed to the mobilewireless device from the second wireless network, the mobile wirelessdevice establishes a connection with the second wireless network. Whenreceiving no paging message and when receiving a paging message thatdoes not include a page addressed to the mobile wireless device from thesecond wireless network, the mobile wireless device tunes the one ormore receivers in the mobile wireless device back to the first wirelessnetwork and subsequently transmits a signaling message to the firstwireless network through the established radio resource connection. In arepresentative embodiment, the first wireless network suspends alltransmit and receive radio resource allocations to the mobile wirelessdevice after receiving the radio resource suspension trigger andcontinues the suspension until receiving the subsequently transmittedsignaling message from the mobile wireless device, while alsomaintaining the established radio resource control connection with themobile wireless device.

In another embodiment, a method to manage radio resources between amobile wireless device and a first wireless network is described. Themethod includes at least the following steps executed by a radio accesssubsystem in the first wireless network when the mobile wireless deviceis associated with the first wireless network through an establishedradio resource control connection and is simultaneously registered witha second wireless network. The radio access subsystem receives a radioresource suspension trigger from the mobile wireless device. Afterreceiving the radio resource suspension trigger, the radio accesssubsystem maintains the established radio resource control connectionand suspends all transmit and receive radio resource allocations to themobile wireless device during at least one paging cycle of the secondwireless network. After receiving a subsequent signaling message fromthe mobile wireless device through the established radio resourcecontrol connection, the radio access subsystem resumes transmit andreceive radio resource allocations to the mobile wireless device. In arepresentative embodiment, the radio resource suspension trigger is asignaling message that includes a predefined combination of values for achannel quality indicator, a precoding matrix indicator and a rankindicator.

In another embodiment, a method to manage radio resources between amobile wireless device and a first wireless network is described. Themethod includes at least the following steps executed by a radio accesssubsystem in the first wireless network when the mobile wireless deviceis associated with the first wireless network through an establishedradio resource control connection and is simultaneously registered witha second wireless network. The radio access subsystem detects that themobile wireless device is a single chip dual standby mobile wirelessdevice. The radio access subsystem calculates a paging cycle for themobile wireless device in the second wireless network. During at leastone paging cycle for the mobile wireless device in the second wirelessnetwork, the radio access subsystem maintains the established radioresource control connection and suspends all transmit and receive radioresource allocations to the mobile wireless device. After receiving asubsequent signaling message from the mobile wireless device through theestablished radio resource control connection, the radio accesssubsystem resumes transmit and receive radio resource allocations to themobile wireless device. In a representative embodiment, the radio accesssubsystem calculates the paging cycle of the second wireless networkusing a local time reference, wherein the first and second wirelessnetworks are synchronized to a common time reference. In arepresentative embodiment, the radio access subsystem detects the mobilewireless device is a single chip dual standby device by a uniqueinternational mobile equipment identifier (IMEI) of the mobile wirelessdevice.

In a further embodiment, a method to manage radio resources between amobile wireless device and a first wireless network is described. Themethod includes at least the following steps executed by the mobilewireless device when the mobile wireless device is associated with thefirst wireless network through an established radio resource controlconnection and is simultaneously registered with a second wirelessnetwork. The mobile wireless device tunes one or more receivers in themobile wireless device to listen for a page address to the mobilewireless device from the second wireless network during a paginginterval. When not receiving the page addressed to the mobile wirelessdevice from the second wireless network, the mobile wireless devicetunes the one or more receivers in the mobile wireless device to thefirst wireless network until a subsequent paging interval. Whenreceiving the page addressed to the mobile wireless device from thesecond wireless network, the mobile wireless device transmits asignaling message to the first wireless network that requests releasingthe radio resource control connection, and subsequently the mobilewireless device establishes a connection with the second wirelessnetwork.

In yet another embodiment, a mobile wireless device is described. Themobile wireless device includes at least an application processor, atransmitter and one or more receivers. The application processor isconfigured to control establishing and releasing connections between themobile wireless device and one or more wireless networks. Thetransmitter is configured to transmit signals to a first wirelessnetwork according to a first wireless communication protocol and to asecond wireless network according to a second wireless communicationprotocol. The one or more receivers are configured to receive signalsfrom the first and second wireless networks. The application processoris further configured to maintain an established radio resource controlconnection when the transmitter transmits a radio resource suspensiontrigger to the first wireless network and at least one receiver tunes toa second wireless network to listen for a page addressed to the mobilewireless device during a paging interval. The application processor isalso configured to establish a connection with the second wirelessnetwork, when receiving the page addressed to the mobile wireless devicefrom the second wireless network during the paging interval. Theapplication processor is additionally configured to send a signalingmessage to the first wireless network through the established radioresource control connection after at least one receiver tunes back tothe first wireless network, when not receiving the page from the secondwireless network during the paging interval. In a representativeembodiment, the radio resource suspension trigger is a signaling messagethat includes a predefined combination of values for a channel qualityindicator, a precoding matrix indicator and a rank indicator.

In another embodiment, a computer program product encoded as computerprogram code in a non-transitory computer readable medium for managingradio resources between a mobile wireless device and a first wirelessnetwork is described. The computer program product includes at least thefollowing computer program code. Computer program code for maintainingan established radio resource control connection with the first wirelessnetwork when listening for a page addressed to the mobile wirelessdevice from a second wireless network during a paging interval. Computerprogram code for tuning one or more receivers in the mobile wirelessdevice to listen for the page addressed to the mobile wireless devicefrom the second wireless network during the paging interval. Computerprogram code for tuning the one or more receivers in the mobile wirelessdevice to the first wireless network when not receiving the pageaddressed to the mobile wireless device from the second wireless networkduring the paging interval until a subsequent paging interval. Computerprogram code for transmitting a signaling message that requests releaseof the radio resource control connection to the first wireless networkafter receiving the page addressed to the mobile wireless device fromthe second wireless network and before establishing a connection withthe second wireless network.

BRIEF DESCRIPTION OF THE DRAWINGS

The described embodiments and the advantages thereof may best beunderstood by reference to the following description taken inconjunction with the accompanying drawings.

FIG. 1 illustrates components of a generic wireless communicationnetwork.

FIG. 2 illustrates components of a CDMA2000 1× (RTT or EV-DO) wirelesscommunication network.

FIG. 3 illustrates components of an LTE (or LTE-Advanced) wirelesscommunication network.

FIG. 4 illustrates a mobile wireless device communicating in parallel tothe CDMA2000 1× (RTT or EV-DO) wireless communication network of FIG. 2and the LTE (or LTE-Advanced) wireless communication network of FIG. 4.

FIG. 5 illustrates elements of a prior art dual signal processing chipmobile wireless device.

FIG. 6 illustrates elements of a representative single signal processingchip mobile wireless device.

FIG. 7 illustrates several transmission modes using one or more antennasof the mobile wireless device.

FIG. 8 illustrates representative protocol stacks between the mobilewireless device and the LTE (or LTE-Advanced) wireless network.

FIG. 9 illustrates a prior art extended service request exchange betweenthe mobile wireless device and the LTE (or LTE-Advanced) wirelessnetwork.

FIGS. 10, 11, 12 and 13 illustrate representative methods to manageradio resources between a mobile wireless device and a wireless network.

FIG. 14 illustrates options for the use of an extended service requestmessage with a representative method to manage radio resources betweenthe mobile wireless device and the wireless network.

DETAILED DESCRIPTION

Wireless networks continue to evolve as network operators deployequipment for new wireless communication technologies based on ongoingstandardization efforts. Mobile wireless devices can providecapabilities to communicate with wireless networks based on two or moredifferent wireless communication technologies, e.g. GSM and UMTS, UMTSand LTE, CDMA2000 1× and LTE, as newer wireless network technologiesoffer advanced capabilities in parallel with earlier wireless networktechnologies that can provide greater geographic area coverage.Different wireless communication technologies can require differenthardware and software processing to transmit and receive wirelesssignals, and a mobile wireless device can includes multiple, separatesignal processing chips to encode and decode wireless signals accordingto the different wireless communication technologies. A dual chip mobilewireless device, for example, can include one chip for a CDMA2000 1×wireless network and a second chip for an LTE wireless network. Withsufficient parallel analog hardware, the dual chip mobile wirelessdevice can communicate with one or both of the wireless networks inparallel. Dual chip mobile wireless devices, however, can be morecomplex, larger, more costly and more power intensive than a single chipmobile wireless device. In some embodiments, the single chip mobilewireless device can communicate with one wireless network at a time outof multiple wireless networks and can provide limited (if any)simultaneous connection capabilities for other parallel wirelessnetworks.

It should be understood that implementations of the same methods andapparatuses described herein can apply to mobile wireless devices thatoperate in different types of wireless networks, particularly one ormore wireless networks that offer connections using two or moredifferent generations or types of wireless communication protocols. Forexample, the same teachings can be applied to a combination of GSM andUMTS networks, LTE and UMTS networks, LTE and CDMA2000 1× networks orother “combined” multiple radio access technology (multi-RAT) wirelessnetworks. The specific examples and implementations described herein arepresented for simplicity in relation to CDMA2000 1×-RTT and LTE wirelessnetworks but can also apply equally to other wireless networkenvironments that use other combinations of wireless accesscommunication protocols.

In embodiments described herein, a single chip mobile wireless devicecan be capable of receiving wireless radio frequency signals from an LTEwireless network or from a CDMA2000 1× wireless network individually butnot from both wireless networks simultaneously (or in some instances,with only limited reception capabilities from both wireless networkssimultaneously). Initially, the single chip mobile wireless device canbe associated with the LTE wireless network, e.g. connected to or campedon the LTE wireless network. The single chip mobile wireless device canbe registered simultaneously with both the LTE wireless network and withthe CDMA2000 1× wireless network. The CDMA2000 1× wireless network canseek to establish a connection with the single chip mobile wirelessdevice by sending a paging message including a page addressed to themobile wireless device during a paging interval. The single chip mobilewireless device can interrupt a packet switched data connection with theLTE wireless network in order to realize a mobile originated voiceconnection or to listen for a page addressed to the mobile wirelessdevice for a mobile terminated circuit switched voice connection to theCDMA2000 1× wireless network. The single chip mobile wireless device cansuspend the packet switched data connection to the LTE wireless networkin order to establish a device originating or device terminated circuitswitched voice connection to the CDMA2000 1× wireless network; however,a higher layer radio resource connection, such as a connection forsignaling between the single chip mobile wireless device and the LTEwireless network, can remain undisturbed during the suspension. In anembodiment, the single chip mobile wireless device can transmit a radioresource suspension trigger to the LTE wireless network to indicate tothe LTE wireless network to suspend radio resource allocation during atleast one paging interval while still maintaining an established radioresource control signaling connection with the single chip mobilewireless device. The single chip mobile wireless device can tune areceiver away from the LTE wireless network and to the CDMA2000 1×wireless network to listen for a paging message that includes a pageaddressed to the single chip mobile wireless device. If no pagingmessage including a page addressed to the single chip mobile wirelessdevice is received from the CDMA2000 1× wireless network, then thesingle chip mobile wireless device can retune the receiver back to theLTE wireless network in a relatively short time period, e.g. withinapproximately 100 ms. A short interruption of the packet switched dataconnection (and of a parallel higher layer signaling connection) to theLTE wireless network can be accommodated without the LTE wirelessconnection being dropped. In a representative embodiment, the singlechip mobile wireless device can transmit a signaling message on theradio resource control signaling connection to the LTE wireless networkindicating that the single chip mobile wireless device is ready for aresumption of radio resource allocations to the single chip mobilewireless device. Active data transfer between the LTE wireless networkand the single chip mobile wireless device during the suspension periodcould have been lost during the short interruption to listen for thepage addressed to the single chip mobile wireless device on the CDMA20001× wireless network during the paging interval if data transfer betweenthe single chip mobile wireless device and the LTE wireless network hadnot been suspended.

After receiving a page addressed to the single chip mobile wirelessdevice from the CDMA2000 1× wireless network, the single chip mobilewireless device can establish a voice connection with the CDMA2000 1×wireless network. The voice connection between the single chip mobilewireless device and the CDMA2000 1× wireless network can result in along interruption to data traffic and signaling traffic between thesingle chip mobile wireless device and the LTE wireless network.Downlink and uplink radio resources assigned by the LTE wireless networkto the single chip mobile wireless device can remain unused during thislong interruption if not suspended beforehand, which can unnecessarilywaste scarce radio resources in the access network portion of the LTEwireless network. A radio resource control (RRC) connection to the LTEwireless network can eventually time out due to a lack ofacknowledgements being sent from the single chip mobile wireless deviceto the LTE wireless network. The RRC connection can enter the idlestate, or the connection between the single chip mobile wireless deviceand the LTE wireless network can be dropped. When retuning the receiverback to the LTE wireless network, the single chip mobile wireless devicecan be required to re-establish a new RRC connection with the LTEwireless network.

In order to listen for pages addressed to the single chip mobilewireless device from the CDMA2000 1× wireless network, the single chipmobile wireless device can tune a receiver to the CDMA2000 1× wirelessnetwork during regular paging intervals. In an embodiment, a CDMA2000 1×wireless network can operate with a paging cycle of approximately 5.12seconds. The single chip mobile wireless device can be aware of aconnection request from the CDMA2000 1× wireless network by listeningfor and receiving paging messages containing pages addressed to thesingle chip mobile wireless device transmitted by the CDMA2000 1×wireless network during appropriate paging intervals. The 3GPPPcommunications standards document 23.272 Release 9 includes an extendedservice request (ESR) message to terminate a connection with the LTEwireless network before listening to (or connecting to) a parallelCDMA2000 1× wireless network. Before tuning its receiver to the CDMA20001× wireless network, a mobile wireless device can send the ESR messageto the LTE wireless network, thereby releasing LTE radio resourcesassigned to the mobile wireless device and also terminating the LTE RRCsignaling connection. Sending the ESR message and subsequently tuning tothe CDMA2000 1× wireless network can be used effectively for mobileoriginated voice connections to the CDMA2000 1× wireless network,particularly as voice connections can last for relatively long periodsof time. For short time intervals, such as when tuning a receiver in asingle chip mobile wireless device to listen for paging messages duringa relatively short time periods spanning approximately 100 ms, with eachshort time period spaced apart at regular time intervals, sending an ESRmessage before each tuning of the receiver to listen for pages from theparallel CDMA2000 1× wireless network can place an unnecessarily highsignaling load on the LTE wireless network. The RRC signaling connectionto the LTE wireless network can be repeatedly released by sending an ESRmessage for each paging interval to listen for a page and thenre-established when receiving no page addressed to the single chipmobile wireless device during the paging interval. In most instances,pages addressed to the single chip mobile wireless device can bereceived much less frequently than the frequency that the pagingintervals can occur. Scarce signaling radio resources can be wasted bythe repeated releasing and re-establishing of the RRC signalingconnection with the LTE wireless network. Sending an ESR message onlyafter receiving a page addressed to the single chip mobile wirelessdevice can reduce signaling loads on the LTE wireless network, therebyimproving signaling efficiency in the radio access portion of the LTEwireless network. In different embodiments, when to transmit the ESRmessage to release the RRC connection with the LTE wireless network canbe balanced against time to respond to the page addressed to the singlechip wireless device in order to establish a connection with theCDMA2000 1× wireless network as described further herein.

FIG. 1 illustrates a representative generic wireless network 100 thatcan include multiple mobile wireless devices 102 connected by radiolinks 126 to radio sectors 104 provided by a radio access network 128.Each radio sector 104 can represent a geographic area of radio coverageemanating from an associated radio node 108 using a radio frequencychannel operating at a selected frequency. Each radio node 108 cangenerate one or more radio sectors 104 to which the mobile wirelessdevice 102 can connect by one or more radio links 126. To form a mobileterminated connection between the mobile wireless device 102 and theradio access network 128, a radio controller 110 in the radio accesssubsystem 106 can instruct the radio node 108 to transmit a signalingmessage, such as a paging message containing a page addressed to themobile wireless device 102. In certain networks, the radio controller110 can also instruct the radio node 108 to transmit a signalingindicator, such as a page indicator bit, in advance of the pagingmessage to provide notice to the mobile wireless device 102 of theforthcoming page. After receiving the page, the mobile wireless device102 can attempt to establish an active connection with the wirelessnetwork 100 by sending a connection request message on a radio frequencychannel. (The connection request can be bundled together with otherinformation into a common message and need not be a distinct connectionrequest message alone.)

In some wireless networks 100, the mobile wireless device 102 can beconnected to more than one radio sector 104 simultaneously. The multipleradio sectors 104 to which the mobile wireless device 102 can beconnected can emanate from a single radio node 108 or from separateradio nodes 108 that can share a common radio controller 110. A group ofradio nodes 108 together with the associated radio controller 110 can bereferred to as a radio access subsystem 106. Typically each radio node108 in a radio access subsystem 106 can include a set of radio frequencytransmitting and receiving equipment mounted on an antenna tower, andthe radio controller 110 connected to the radio nodes 108 can includeelectronic equipment for controlling and processing transmitted andreceived radio frequency signals. The radio controller 110 can managethe establishment, maintenance and release of the radio links 126 thatconnect the mobile wireless device 102 to the radio access network 128.

Radio resources that form the radio links 126 in the radio sectors 104can be shared using a number of different multiplexing techniques,including time division, frequency division, code division, spacedivision and combinations thereof. A radio resource control (RRC)signaling connection can be used to communicate between the mobilewireless device 102 and the radio controller 110 in the radio accesssubsystem 106 of the radio access network 128 including requests for anddynamic allocations of radio resources to multiple mobile wirelessdevices 102. Suspension of allocation of radio resources to a mobilewireless device 102 can occur without disestablishing the radio resourcesignaling connection to the mobile wireless device 102 as describedfurther herein.

The radio access network 128, which provides radio frequency air linkconnections to the mobile wireless device 102, connects also to a corenetwork 112 that can include a circuit switched domain 122, usually usedfor voice traffic, and a packet switched domain 124, usually used fordata traffic. Radio controllers 110 in the radio access subsystems 106of the radio access network 128 can connect to both a circuit switchingcenter 118 in the circuit switched domain 122 and a packet switchingnode 120 in the packet switched domain of the core network 112. Thecircuit switching center 118 can route circuit switched traffic, such asa voice call, to a public switched telephone network (PSTN) 114. Thepacket switching node 120 can route packet switched traffic, such as a“connectionless” set of data packets, to a public data network (PDN)116.

FIG. 2 illustrates a representative CDMA2000 1× wireless network 200that can include elements comparable to those described for the genericwireless network 100 shown in FIG. 1. Multiple mobile stations 202 canconnect to one or more radio sectors 204 through radio frequency links226. Each radio sector 204 can radiate outward from a base transceiverstation (BTS) 208 that can connect to a base station controller (BSC)210, together forming a base station subsystem (BSS) 206. Multiple basestation subsystems 206 can be aggregated to form a radio access network228. Base station controllers 210 in different base station subsystems206 can be interconnected. The base station controllers 210 can connectto both a circuit switched domain 222 that use multiple mobile switchingcenters (MSC) 218 and a packet switched domain 224 formed with packetdata service nodes (PDSN) 220, which together can form a core network212 for the wireless network 200. As with the generic wireless network100 described above, the circuit switched domain 222 of the core network212 can interconnect to the PSTN 114, while the packet switched domain224 of the core network 212 can interconnect to the PDN 116.Establishing connections on the CDMA2000 1× wireless network 200 candepend on the mobile station 202 receiving a page from the BSS 206indicating an incoming connection. The mobile station 202 can berequired to listen for pages during specific paging intervals. Withoutreception of the page, the mobile station 202 can be unaware of arequest to form a connection between the mobile station 202 and theCDMA2000 1× wireless network 200.

FIG. 3 illustrates a representative Long Term Evolution (LTE) wirelessnetwork 300 architecture designed as a packet switched networkexclusively. A mobile terminal 302 can connect to an evolved radioaccess network 322 through radio links 326 associated with radio sectors304 that emanate from evolved Node B's (eNodeB) 310. The eNodeB 310includes the functions of both the transmitting and receiving basestations (such as the BTS 208 in the CDMA2000 1× wireless network 200)as well as the base station radio controllers (such as the BSC 210 inthe CDMA2000 1× wireless network 200). The equivalent core network ofthe LTE wireless network 300 is an evolved packet core network 320including serving gateways 312 that interconnect the evolved radioaccess network 322 to public data network (PDN) gateways 316 thatconnect to external internet protocol (IP) networks 318. Multiple eNodeB310 can be grouped together to form an evolved UTRAN (eUTRAN) 306. TheeNodeB 310 can also be connected to a mobility management entity (MME)314 that can provide control over connections for the mobile terminal302.

FIG. 4 illustrates a diagram 400 of a mobile wireless device 102 incommunication with both the LTE wireless network 300 and with theCDMA2000 1× wireless network 200. The CDMA2000 1× wireless network 200can connect to the circuit switch based public switched telephonenetwork (PSTN) 114 through a mobile switching center (MSC) 218. The MSC218 of the CDMA2000 1× wireless network 200 can be interconnected to theMME 314 of the LTE wireless network 300 to coordinate call signaling forthe mobile wireless device 102. In some embodiments, the CDMA2000 1×wireless network 200 can seek to establish a connection through theradio links 226 with the mobile wireless device 102, e.g. to establish avoice connection between the mobile wireless device 102 and the PSTN114. The CDMA2000 1× wireless network 200 can transmit a page message tothe mobile wireless device 102 using the radio links 226 to indicate theavailability of an incoming voice connection. Unless a receiver in themobile wireless device 102 is tuned to listen for the page message fromthe CDMA2000 1× wireless network 200 during the appropriate paginginterval, the mobile wireless device 102 can be connected to the LTEwireless network 300 during the paging interval and can be unaware ofthe incoming voice connection. A dual chip mobile wireless device 102can be connected to the LTE wireless network 300 and listen to theCDMA2000 1× wireless network 200 simultaneously, but a single chipmobile wireless device 102 with limited receive capabilities can be onlycapable of listening to one cellular wireless network at a time. Asdescribed herein, the single chip mobile wireless device 102 canperiodically listen for page messages from the CDMA2000 1× wirelessnetwork while simultaneously maintaining at least a signaling connectionto the LTE wireless network 300 to minimize signaling messages to theLTE wireless network 300. The LTE wireless network 300 can suspend radioresource allocations to the single chip mobile wireless device 102during the page intervals in order to reuse the radio resources forother mobile wireless devices 102 in communication with the LTE wirelessnetwork 300.

FIG. 5 illustrates select wireless signal processing elements 500 thatcan be contained in a prior art dual chip wireless transmitter/receiver(TX/RX) 516 within a dual chip mobile wireless device 102. An LTE signalprocessing chip 502 can be used for connections between the dual chipmobile wireless device 102 and the LTE wireless network 300, while aCDMA2000 1× signal processing chip 504 can be used for connectionsbetween the dual chip mobile wireless device 102 and the CDMA2000 1×wireless network 200. Each signal processing chip can be connected to aset of antennas through which radio frequency signals can be transmittedand received with respective wireless networks. The LTE signalprocessing chip 502 can be connected to a transmitting antenna 506 andto a pair of receive antennas 508/510. Multiple receive antennas can beused to improve performance through various forms of receive diversityand can be required based on a standardized wireless communicationprotocol. With the separate CDMA2000 1× signal processing chip 504, thedual chip mobile wireless device 102 can transmit and receive radiofrequency signals with the CDMA2000 1× wireless network 200 through atransmit antenna 512 and a receive antenna 514, while simultaneouslytransmitting and receiving radio frequency signals with the LTE wirelessnetwork 300 through the separate transmit antenna 506 and receiveantennas 508/510. The LTE signal processing chip 502 and the CDMA2000 1×signal processing chip 504 can be connected to each other in order tocoordinate radio frequency signal communication with their respectivewireless networks. The dual chip wireless transmitter/receiver 516,while flexible, can be more expensive, consume more power and occupymore space than a compact, low power single chip wirelesstransmitter/receiver as shown in FIG. 6.

FIG. 6 illustrates a diagram 600 of a single chip wirelesstransmitter/receiver 614 that can reside in a single chip wirelessmobile wireless device 102 that can communicate with the LTE wirelessnetwork 300 or the CDMA2000 1× wireless network 200 separately but notsimultaneously. When connected to the LTE wireless network 300, thesingle chip mobile wireless device 102 can use a single transmitter (Tx)608 and dual receivers (Rx) 610/612. When connected to the CDMA2000 1×wireless network 200, the single chip mobile wireless device 102 can usethe single transmitter 608 and either one receiver (Rx 610 or Rx 612) ordual receivers (Rx 610 and Rx 612). Use of dual receivers for both theLTE wireless network 300 and the CDMA2000 1× wireless network 200 canprovide higher receive signal quality and therefore higher datathroughput and/or greater connection reliability under adverse signalconditions. An interconnect block 606 can allow either an LTE signalprocessing 602 block or a CDMA2000 1× signal processing block 604 totransmit and receive radio signals through the transmitter 608 and oneor both of the receivers 610/612 respectively. Within the single chipwireless mobile wireless device 102, the single chip wirelesstransmitter/receiver 614 can be connected to an application processor(not shown) that can perform “higher layer” functions such asestablishing connections for applications and forming messages to becommunicated with various wireless networks, while the single chipwireless transmitter/receiver 614 can perform “lower layer” functionssuch as ensuring integrity of transmitted and received radio frequencysignals that carry messages for the application processor.

FIG. 7 illustrates four different transmission and reception methodsthat can be used for communication of radio frequency signals betweenthe mobile wireless device 102 and radio access networks 228/322 ofwireless networks 200/300. Multiple transmit and/or receive antennas canbe used for transmission signal path diversity to improve performance aswell as for spatial multiplexing to increase throughput. A singletransmitter, single receiver radio frequency channel 700 provides abasic form of communication with one transmitter 702 and one receiver704 used at each end. A single transmitter, multiple receiver radiofrequency channel 710 can provide receive diversity to improve receivesignal strength by combining signals received from each of multipleparallel receive antennas at one end. As shown signals from the singletransmitter 702 can be received by two different antennas 706. Whileonly two receive antennas are shown in FIG. 7, more than two receiveantennas can also be specified by wireless communication protocols andused in advanced mobile wireless devices. A multiple transmitter, singlereceiver radio frequency channel 720 can provide a form of transmitdiversity by sending the same data (although possibly encodeddifferently) through each of multiple antennas. The single antennareceiver 704 can combine information received from each of the twotransmit antennas 708 to improve receive signal performance. Finally, amultiple transmitter, multiple receiver radio frequency communicationchannel 730 can provide for a multiple input multiple output (MIMO) formof communication that can both improve receive signal performance andincrease data rates. Parallel data streams can be transmitted by each ofthe multiple transmitting antennas, and the multiple receiving antennascan separate the received signals to reconstruct the parallel datastreams. The use of multiple antennas (including both transmit andreceive antennas) can be a critical requirement in advanced wirelesscommunication protocols to increase robustness and achieve higher datatransmission rates.

As illustrated in FIG. 8, the mobile wireless device 102 can connect tothe LTE wireless network 300 using wireless communication protocolstacks 800/810 The user plane protocol stack 810 can include a physicallayer (PHY) to ensure integrity of multiple “transport” channels overradio links 326 between the mobile wireless device 102 and the eNodeB310 for the LTE wireless network 300. (Equivalent protocol stacks canalso be used for the CDMA2000 1× wireless network 200.) The mediumaccess control (MAC) layer can map multiple logical channels to thetransport channels, while the radio link control (RLC) layer can formatdata and signaling messages for communication between the mobilewireless device 102 and the LTE wireless network 300. The packet dataconvergence protocol (PDCP) layer can control compression and encryptionof data messages received from higher layers for communication throughthe LTE wireless network 300. The control plane protocol stack 800 caninclude the same layers as the user plane protocol stack 810 andadditional layers including the radio resource control (RRC) layer toestablish, maintain, share and disestablish radio resources forcommunication through the radio links 326. The RRC/PDCP/RLC/MAC/PHYprotocol layers can form an “access stratum” that connects the mobilewireless device 102 with the eNodeB 310 of the LTE wireless network 300.The control plane protocol stack 800 can also include a higher layer“non-access stratum” (NAS) that can connect the mobile wireless device102 with a mobility management entity (MME 314) in the LTE wirelessnetwork 300. The NAS layer can be used when associating the mobilewireless device 102 with the LTE wireless network 300 and forestablishing and releasing bearer channels through the LTE wirelessnetwork 300.

FIG. 9 illustrates a prior art message exchange 900 between the mobilewireless device 102 and the eNodeB 310 of the LTE wireless network 300to release a radio resource control (RRC) connection. When the mobilewireless device 102 intends to originate a voice connection with theCDMA2000 1× wireless network 200, the mobile wireless device candisconnect from the LTE wireless network 300 by sending an extendedservice request (ESR) message 902. The ESR message can be appropriatewhen the mobile wireless device 102 intends to tune its receiver awayfrom the LTE wireless network 300 to the CDMA2000 1× wireless network200 for a relatively long time period, such as during a voiceconnection. The LTE wireless network 300 can release the existing RRCconnection and provide an indication of the release to the mobilewireless device 102 by sending an RRC connection release message 904.The release of the RRC connection can ensure an orderly termination ofan existing connection with the LTE wireless network 300; however, whenthe mobile wireless device 102 intends to re-establish a connection withthe LTE wireless network 300, a new RRC connection must be established.For brief and relatively frequent interruptions of connections with theLTE wireless network 300, such as when tuning a receiver from the LTEwireless network 300 to the CDMA2000 wireless network 200 to listen fora page addressed to the mobile wireless device 102 during regularlytransmitted paging intervals, releasing the RRC connection and thenre-establishing the RRC connection for each paging interval canunnecessarily add to signaling loads in the evolved radio access network322 of the LTE wireless network 300.

In representative embodiments, the single chip mobile wireless device102 can monitor paging messages from the CDMA2000 1× wireless network200 without sending an ESR message 902 to the LTE wireless network 300before tuning the receiver to listen for the paging messages during apaging interval on the CDMA2000 1× wireless network 200. In someembodiments, after receiving a paging messages that includes a pageaddressed to the single chip mobile wireless device 102 from theCDMA2000 1× wireless network 200, the single chip mobile wireless device102 can transmit an ESR message 902 to the LTE wireless network 300after receiving the page and before completing a connection to theCDMA2000 1× wireless network 200. In other embodiments, the single chipmobile wireless device 102 can transmit a suspension message to the LTEwireless network 300 rather than an ESR message 902 before tuning thereceiver to listen for paging messages on the CDMA2000 1× wirelessnetwork 200. After receiving the suspension message, the LTE wirelessnetwork 300 can suspend allocation of radio resources in the accessnetwork until receiving a subsequent signaling message from the singlechip mobile wireless device 102. The RRC connection can be maintainedduring a brief suspension period and can be released following a longersuspension period based on a timeout period. By suspending but notreleasing the RRC connection for brief periods while tuning one or morereceivers in the single chip mobile wireless device 102 between the LTEwireless network 300 and the CDMA2000 1× wireless network 200, thesingle chip mobile wireless device 102 can resume a connection to theLTE wireless network 300 without having to re-establish a new RRCconnection to the LTE wireless network 300.

FIG. 10 illustrates a representative method 1000 to manage radioresources between a mobile wireless device 102 and a first wirelessnetwork when the mobile wireless device 102 is simultaneously associatedwith the first wireless network and registered with a second wirelessnetwork. In step 1002, the mobile wireless device 102 transmits a radioresource suspension trigger to the first wireless network. The radioresource suspension trigger can indicate to the first wireless networkthat the mobile wireless device 102 will tune its receiver to the secondwireless network for a period of time during which no radio resourcesneed be allocated to the mobile wireless device 102 by the firstwireless network. The first wireless network can suspend allocation ofradio resources to the mobile wireless device 102 until receiving anindication from the mobile wireless device 102 to resume allocation ofradio resources. In an embodiment, the indication to resume radioresource allocation can be the reception of a signaling message from themobile wireless device 102 by the first wireless network following thesuspension. In step 1004, the mobile wireless device 102 tunes one ormore receivers in the mobile wireless device 102 to the second wirelessnetwork in order to listen for paging messages transmitted during apaging interval. In step 1006, the mobile wireless device 102 determinesif a paging message containing a page addressed to the mobile wirelessdevice 102 has been received from the second wireless network during thepaging interval. If a page addressed to the mobile wireless device 102is received from the second wireless network during the paging intervalin step 1006, then in step 1012, the mobile wireless device 102establishes a connection with the second wireless network. If no pagingmessage is received or if a paging message is received with a pageaddressed to a different device during the paging interval in step 1006,then in step 1008, the mobile wireless device 102 re-tunes the one ormore receivers from the second wireless network back to the firstwireless network. In step 1010, the mobile wireless device 102 transmitsa signaling message to the first wireless network, thereby indicating tothe first wireless network its readiness to resume transmission andreception with the first wireless network. In response to the signalingmessage, the first wireless network can resume allocations of radioresources to the mobile wireless device 102. No ESR message need betransmitted to cause the suspension of radio resource allocation to themobile wireless device 102, and an RRC signaling connection between themobile wireless device 102 and the first wireless network can remain inplace during the suspension period.

In a representative embodiment, the first wireless network is an LTEwireless network 300 and the second wireless network is a CDMA2000 1×wireless network 200. The single chip mobile wireless device 102transmits the suspension trigger to the LTE wireless network 300 beforetuning a receiver away from the LTE wireless network 300 to the CDMA20001× wireless network 200 to listen for pages received from the CDMA20001× wireless network 200. The suspension trigger from the single chipmobile wireless device 102 can indicate to the LTE wireless network 300that the single chip mobile wireless device 102 will tune away itsreceiver for a period of time. The transmitted suspension trigger candiffer from the extended service request (ESR) message in that an RRCconnection between the single chip mobile wireless device 102 and theLTE wireless network 300 can be suspended but not necessarily released.In one embodiment, the suspension trigger includes a predetermined setof values for a signaling message transmitted regularly to the LTEwireless network 300 by the single chip mobile wireless device 102. Inrepresentative embodiments, the suspension trigger can be a predefinedcombination of values for one or more of the channel quality information(CQI), the pre-coding matrix indicator (PMI) and the rank indicator(RI). Upon receipt of the suspension trigger, the LTE wireless network300 suspends allocating radio resources in both the downlink and uplinkdirections to the single chip mobile wireless device 102. The radioresource control (RRC) connection between the LTE wireless network 300and the single chip mobile wireless device 102 is maintained by the LTEwireless network 300 during the suspension (at least for a period oftime). The LTE wireless network 300 suspends data transmission to thesingle chip mobile wireless device 102 and later resumes datatransmission to the single chip mobile wireless device 102 without aloss of data packets in the downlink direction, thereby maintaining datatransmission integrity. The radio resources can be assigned to othermobile wireless devices 102 by the LTE wireless network 300 during thesuspension, thereby improving access network radio resource efficiency.

When no page addressed to the single chip mobile wireless device 102 isreceived by the single chip mobile wireless device 102 from the CDMA20001× wireless network 200 during the time period when its receiver istuned to the CDMA2000 1× wireless network 200, the single chip mobilewireless device 102 returns to the LTE wireless network 300 (i.e.retunes its receiver back to the LTE wireless network 300). Theinterruption of the LTE connection can be relatively short, e.g.approximately 100 ms. After retuning its receiver back to the LTEwireless network 300, the single chip mobile wireless device 102transmits a signaling message to the LTE wireless network 300 indicating(directly or indirectly) that its receiver has been retuned back to theLTE wireless network 300. The LTE wireless network 300 can then resumeallocation of radio resources to the single chip mobile wireless device102. Both the suspension trigger and the “resume” indication to the LTEwireless network 300 can use a regularly transmitted signaling messagesuch as the CQI/PMI/RI message, and as such no extra signaling load canbe required for the LTE wireless network 300 connections to realize thesuspension and resumption of the LTE wireless network 300 connectionwith the single chip mobile wireless device 102.

When the single chip mobile wireless device 102 receives a pageaddressed to the single chip mobile wireless device 102 from theCDMA2000 1× wireless network 200 during the time period when itsreceiver is tuned to the CDMA2000 1× wireless network 200, the singlechip mobile wireless device 102 establishes a mobile terminatedconnection to the CDMA2000 1× wireless network 200. The receiver in thesingle chip mobile wireless device 102 remains tuned to the CDMA2000 1×wireless network 200 while the CDMA2000 1× wireless network 200connection remains active. For a sufficiently long connection to theCDMA2000 1× wireless network 200, the parallel RRC connection to the LTEwireless network 300 eventually times out. At the end of the connectionto the CDMA2000 1× wireless network 200, the single chip mobile wirelessdevice 102 tunes its receiver back to the LTE wireless network 300 andre-establishes an RRC connection to the LTE wireless network 300 inorder to resume active data transfer with the LTE wireless network 300.

FIG. 11 illustrates another representative method 1100 to manage radioresources between the mobile wireless device 102 and the first wirelessnetwork. In step 1102, a radio access subsystem in the first wirelessnetwork receives a radio resource suspension trigger from the mobilewireless device 102. In step 1104, the radio access subsystem in thefirst wireless network maintains an existing radio resource control(RRC) connection between the first wireless network and the mobilewireless device 102. In step 1106, the radio access subsystem in thefirst wireless network suspends allocation of radio resources in bothtransmit and receive directions to the mobile wireless device 102 duringone or more paging cycles of a second wireless network. In someembodiments, the first wireless network can be aware of specific timeperiods that correspond to paging cycles for the second wirelessnetwork, while in other embodiments, the first wireless network can beunaware of specific time periods for the paging cycles. The suspensionof radio resource allocations to the mobile wireless device 102continues until the radio access subsystem in step 1108 determines thata signaling message from the mobile wireless device 102 has beenreceived. The signaling message indicates to the first wireless networkthat the mobile wireless device 102 is ready to resume transmission andreception through the suspended connection to the first wirelessnetwork. In step 1110, the first wireless network resumes allocationradio resources in transmit and receive directions to the mobilewireless device 102.

FIG. 12 illustrates another representative method 1200 to manage radioresources between the mobile wireless device 102 and a first wirelessnetwork. When the mobile wireless device is associated with the firstwireless network and is simultaneously registered with a second wirelessnetwork, the mobile wireless device 102 in step 1202 tunes at least onereceiver in the mobile wireless device 102 to the second wirelessnetwork during a paging interval of the second wireless network. In step1204, the mobile wireless device 102 determines whether a page addressedto the mobile wireless device 102 is received during the paginginterval. When a page addressed to the mobile wireless device 102 isreceived during the paging interval, the mobile wireless device in step1208 transmits a signaling message to the first wireless network thatrequests release of the radio resource control (RRC) connection betweenthe mobile wireless device 102 and the first wireless network. Arepresentative RRC release message is an ESR message. In step 1210, themobile wireless device 102 establishes a connection between the mobilewireless device 102 and the second wireless network in response to thereceived page addressed to the mobile wireless device 102. The signalingmessage that requests release of the RRC connection can effectivelyrelease the previous connection between the mobile wireless device 102and the first wireless network. When no page addressed to the mobilewireless device 102 is received during the paging interval, the mobilewireless device 102 in step 1206 re-tunes the one or more receivers backto the first wireless network after the paging interval. The cycle thenrepeats for the next paging interval, and thus the mobile wirelessdevice 102 tunes the one or more receivers back and forth between aconnection to the first wireless network and a “listening” mode during apaging interval to the second wireless network. The connection to thefirst wireless network is released only when a page addressed to themobile wireless device 102 is received from the second wireless networkduring one of the paging intervals.

In a representative embodiment, the first and second wireless networkscan be the LTE wireless network 300 and the CDMA2000 1× wireless network200 respectively. When a connection with the LTE wireless network 300 issuspended, no radio resources can be allocated by the LTE wirelessnetwork 300 to the single chip mobile wireless device 102, and thesingle chip mobile wireless device 102 can listen for paging messagesfrom the CDMA2000 1× wireless network 200 without losing data packetsfrom the active connection with the LTE wireless network 300. During theCDMA2000 1× wireless network 200 paging time slot, the single chipmobile wireless device 102 cannot transmit messages on the LTE wirelessnetwork 300. If no page addressed to the mobile wireless device 102 isreceived from the CDMA2000 1× wireless network 200, the single chipmobile wireless device 102 can resume the data connection with the LTEwireless network 300 by sending a signaling message to the LTE wirelessnetwork 300. The LTE wireless network 300 can resume allocating radioresources to the single chip mobile wireless device 102 after receivingthe signaling message.

FIG. 13 illustrates another representative method 1300 to manage radioresources between a mobile wireless device 102 and a first wirelessnetwork when the mobile wireless device 102 is associated with the firstwireless network and is simultaneously registered with a second wirelessnetwork. In step 1302, the first wireless network detects the mobilewireless device 102 is a single chip dual standby (SCDS) mobile wirelessdevice. By detecting the mobile wireless device 102 is an SCDS device,other mobile wireless devices that are not SCDS devices operating in thesame first wireless network can continue to be allocated radioresources, i.e. the suspension of radio resource allocation in the stepsdescribed further below can be applied only to SCDS devices. Inrepresentative embodiments, an SCDS mobile wireless device can indicateto the first wireless network that it is an SCDS mobile wireless devicethrough a device capability indicator or through a feature bit;alternatively, the first wireless network can detect that the mobilewireless device 102 is an SCDS mobile wireless device by recognizingcapabilities of the mobile wireless device 102 by a unique identifierfor the mobile wireless device 102, such as an international mobileequipment identity (IMEI) or an international mobile subscriber identity(IMSI). In step 1304, the first wireless network calculates at least onepaging cycle for the second wireless network. The first and secondwireless networks can be interconnected directly or indirectly such thatpaging intervals for mobile wireless device 102 in the second wirelessnetwork can be determined by the first wireless network. The firstwireless network, in step 1306, maintains a radio resource control (RRC)connection with the mobile wireless device 102. In step 1308, the firstwireless network suspends radio resource allocations for both transmitand receive directions (uplink and downlink transmissions) during atleast one paging cycle of the second wireless network. The RRC signalingconnection between the mobile wireless device 102 and the first wirelessnetwork is maintained while radio resource allocations to the mobilewireless device 102 are suspended by the first wireless network. In step1310, the first wireless network determines whether a signaling messageis received from the mobile wireless device 102. When receiving asignaling message from the mobile wireless device 102, the firstwireless network resumes allocation of radio resources for transmit andreceive directions to the mobile wireless device 102 in step 1312. Untila signaling message is received from the mobile wireless device 102, noresource allocations to the mobile wireless device 102 occur. When nosignaling message is received by the first wireless network, eventuallya timer for the RRC connection expires, and the first wireless networkdrops the RRC connection with the mobile wireless device 102. When theRRC connection has dropped, after the mobile wireless device 102re-tunes its receiver from the second wireless network back to the firstwireless network, an RRC connection to the first wireless network needsto be re-established.

In a representative embodiment, the first wireless network and thesecond wireless network can be the LTE wireless network 300 and theCDMA2000 1× wireless network respectively. The single chip mobilewireless device 102 can be connected to (or camped on) the LTE wirelessnetwork 300, which can be synchronized to a common time reference as theCDMA2000 1× wireless network 200. The single chip mobile wireless device102 can also be registered simultaneously with the CDMA2000 1× wirelessnetwork 200. A representative common time reference can be based on aglobal positioning system (GPS) time reference. System clocks within theLTE wireless network 300 and the CDMA2000 1× wireless network 200 canboth use the same GPS time reference, and both the LTE wireless network300 and the CDMA2000 1× wireless network 200 can use the system time andthe international mobile equipment identity (IMEI) or the internationalmobile subscriber identity (IMSI) of the single chip mobile wirelessdevice 102 to calculate paging time slots and paging time intervals forthe single chip mobile wireless device 102. Using the paging time slotand paging time interval calculations, the LTE wireless network 300 canknow when a single chip mobile wireless device 102 can tune away tolisten for paging messages from the CDMA2000 1× wireless network 200.The LTE wireless network 300 can suspend an active data connection tothe single chip mobile wireless device 102 by not allocating radioresources to the single chip mobile wireless device 102 during theCDMA2000 1× wireless network 200 paging time slots for the single chipmobile wireless device 102. With timing of the LTE wireless network 300and the CDMA2000 1× wireless network 200 synchronized to a common timereference, no suspension trigger from the single chip mobile wirelessdevice 102 is needed, as the LTE wireless network 300 can determine thetiming of the CDMA2000 1× wireless network 200 paging time slots for thesingle chip mobile wireless device 102.

FIG. 14 illustrates a signaling message exchange 1400 between the mobilewireless device 102 and the CDMA2000 1× wireless network 200 as well asthe LTE wireless network 300 when a page 1402 addressed to the mobilewireless device 102 is received by the mobile wireless device 102 whilelistening to the CDMA2000 1× wireless network 200 during a paging timeinterval. Following receipt of the page 1402 addressed to the mobilewireless device 102, the mobile wireless device 102 can send an ESRmessage to the LTE wireless network 300 during one of three differenttime periods. The first time period occurs after receiving the page 1402from the CDMA2000 1× wireless network 200 and before sending a pageresponse 1406 back to the CDMA2000 1× wireless network 200. The secondtime period occurs after sending the page response 1406 to the CDMA20001× wireless network 200 and before receiving an optional acknowledgement(Ack 1408) or an extended channel assignment 1412 message from theCDMA2000 1× wireless network 200. The third time period occurs afterreceiving the optional acknowledgement (Ack 1408) or an extended channelassignment 1412 message from the CDMA2000 1× wireless network 200 andbefore an active connection with traffic 1416 with the CDMA2000 1×wireless network 200. The ESR message can be sent to the LTE wirelessnetwork 300 during one of the three time periods. The transmission ofthe ESR message to the LTE wireless network 300 can be realized as a“best effort” transmission in that the single chip mobile wirelessdevice 102 can choose not to wait for acknowledgement from the LTEwireless network 300 in response to the transmitted ESR message. (Noacknowledgement from the LTE wireless network 300 to the mobile wirelessdevice 102 is shown in FIG. 14). With “best effort” transmission, thesingle chip mobile wireless device 102 can assume that the transmittedESR message is received properly by the LTE wireless network 300. By notwaiting for an acknowledgement from the LTE wireless network 300, thesingle chip mobile wireless device 102 can proceed to establish themobile terminated call to the CDMA2000 1× wireless network 200 withminimal delay.

In one embodiment shown in FIG. 14, after receiving the page 1402addressed to the mobile wireless device 102 from the CDMA2000 1×wireless network 200, the mobile wireless device 102 can tune the one ormore receivers back to the LTE wireless network 300 and send an ESRmessage 1404 to the LTE wireless network 300 and subsequently send apage response 1406 to the CDMA2000 1× wireless network 200. Aftersending the ESR 1404 message to the LTE wireless network 300, the mobilewireless device 102 can tune the one or more receivers back to theCDMA2000 1× wireless network 200 without waiting for an acknowledgementof the ESR 1404 message from the LTE wireless network 300. The mobilewireless device 102 can send the page response 1406 to the CDMA2000 1×wireless network 200 and complete establishment of a connection betweenthe mobile wireless device 102 and the CDMA2000 1× wireless networkafter sending the ESR 1404 to the LTE wireless network 300.

In another embodiment illustrated in FIG. 14, the mobile wireless device102 responds to the page 1402 addressed to the mobile wireless device102 from the CDMA2000 1× wireless network 200 with the page response1406 and then re-tunes one or more receivers in the mobile wirelessdevice 102 from the CDMA2000 1× wireless network 200 back to the LTEwireless network 200 to send an ESR message 1410 to the LTE wirelessnetwork 300. The mobile wireless device 102 can simultaneously keep onereceiver listening to the CDMA2000 1× wireless network 200 for anoptional acknowledgement 1408 message and for an extended channelassignment message 1412 from the CDMA2000 1× wireless network 200 beforeexchanging traffic 1416 with the CDMA2000 1× wireless network 200. Bysending the page response 1406 to the CDMA2000 1× wireless network 200before sending the ESR 1410 message to the LTE wireless network 300,establishment of the connection between the mobile wireless device 102and the CDMA2000 1× wireless network 200 can proceed without delay.

In a further embodiment illustrated in FIG. 14, the mobile wirelessdevice 102 can wait to send an ESR message 1414 to the LTE wirelessnetwork 200 until after receiving the extended channel assignmentmessage 1412 from the CDMA2000 1× wireless network 200 but beforetraffic 1416 with the CDMA2000 1× wireless network 200 starts. Inchoosing between each of the embodiments described above that differ bywhen the ESR message is sent, the mobile wireless device 102 can tradeoff between an earlier response to the LTE wireless network 300 that canfree up radio resources for the LTE wireless network 300 sooner and amore rapid response to the CDMA2000 1× wireless network 200 to speedestablishing a connection with the CDMA2000 1× wireless network 200.

In some embodiments, the LTE wireless network 300 can suspend radioresource allocation to a single chip mobile wireless device 102 based onknowledge of one or more features of the single chip mobile wirelessdevice 102. The single chip mobile wireless device 102 can indicate oneor more of its features by transmitting to the LTE wireless network 300a device capability indicator and/or one or more feature bits in apre-determined message, such as during power up and/or registration ofthe mobile wireless device 102 with the LTE wireless network 300. TheLTE wireless network 300 can also determine features of the single chipmobile wireless device 102 based on knowledge of the device's uniqueinternational mobile equipment identity (IMEI), which can also becommunicated at power up and/or registration. The LTE wireless network300 can target suspension of LTE wireless network 300 connections forselect single chip mobile wireless devices 102 while allowing continuousconnections for other mobile wireless devices 102 that are not singlechip mobile wireless device 102, such as for dual chip mobile wirelessdevices.

In an embodiment, the single chip mobile wireless device 102 can use onetransmit path and one receive path for a connection with the LTEwireless network 300 and simultaneously listen for paging messages onthe CDMA2000 1× wireless network 300 through a separate receive path.This mode of operation of the single chip mobile wireless device 102 canbe referred to as a “no RX diversity” mode. A single receive path modecan have lower receive signal quality than a dual receive path mode;however, the signal quality can be sufficient in some circumstances tomaintain a connection with the LTE wireless network 300. In someembodiments, the single chip mobile wireless device 102 can indicate tothe LTE wireless network 300 use of a “no RX diversity” mode by sendinga pre-determined combination of values of the CQI/PMI/RI to the LTEwireless network 300. In other embodiments, the single chip mobilewireless device 102 cannot indicate to the LTE wireless network 300explicitly of use of a “no RX diversity” mode, although the channelsignal quality indicated in any CQI sent to the LTE wireless network 300when using only a single receiver can be less than when using a dualreceiver.

The LTE wireless network 300 can suspend allocating radio resources foran active data connection to the single receive path mobile wirelessdevice when the LTE wireless network 300 detects an “out of sync”condition. An “out of sync” condition can be declared when no data canbe received and correctly decoded from the single chip mobile wirelessdevice 102 for a pre-determined period of time. The “out of sync”condition can be triggered by an uplink data outage for a relativelyshort period of time (e.g. shorter than the period of time for a loss ofRRC connection). The LTE wireless network 300 can resume allocation ofradio resources to the single chip mobile wireless device 102 uponreception of a correctly decoded signaling message (or data message) inthe uplink direction. When the connection between the LTE wirelessnetwork 300 and the single chip mobile wireless device 102 remains outof sync for an extended period of time, then the LTE wireless network300 can release the RRC connection based on a pre-determined time outperiod. Minimal data loss can occur during short periodic interruptionsof an active connection between the LTE wireless network 300 and thesingle chip mobile wireless device 102 if the LTE wireless network 300suspends radio resource allocation quickly upon detecting an “out ofsync” condition. The single chip mobile wireless device 102 can listenfor paging messages from the CDMA2000 1× wireless network 200 and returnto the LTE wireless network 300 in short order if no page addressed tothe single chip mobile wireless device 102 is received. The RRCconnection to the LTE wireless network 300 can remain up and need not bere-established when listening for the pages during the periodic pagingintervals on the CDMA2000 1× wireless network 200. If a page addressedto the single chip mobile wireless device 102 is received from theCDMA2000 1× wireless network 200, then the single chip mobile wirelessdevice 102 can form a mobile terminated connection with the CDMA2000 1×wireless network 200. This connection between the CDMA2000 1× wirelessnetwork 200 and the single chip mobile wireless device 102 can result inan extended out of sync condition leading to an RRC connection releaseby the LTE wireless network 300.

In some embodiments, the single chip mobile wireless device 102 canelect to not send an ESR message to the LTE wireless network 300 torelease the RRC connection to the LTE wireless network 300. Instead theRRC connection can be released by the LTE wireless network 300 followinga time out period due to inactivity when the single chip mobile wirelessdevice 102 is connected to the CDMA2000 1× wireless network 200.

Various aspects of the described embodiments can be implemented bysoftware, hardware or a combination of hardware and software. Thedescribed embodiments can also be encoded as computer program code on anon-transitory computer readable medium. The non-transitory computerreadable medium is any data storage device that can store data which canthereafter be read by a computer system. Examples of the non-transitorycomputer readable medium include read-only memory, random-access memory,CD-ROMs, DVDs, magnetic tape and optical data storage devices. Thecomputer program code can also be distributed over network-coupledcomputer systems so that the computer program code is stored andexecuted in a distributed fashion.

The various aspects, embodiments, implementations or features of thedescribed embodiments can be used separately or in any combination. Theforegoing description, for purposes of explanation, used specificnomenclature to provide a thorough understanding of the describedembodiments. However, it will be apparent to one skilled in the art thatthe specific details are not required in order to practice the describedembodiments. Thus, the foregoing descriptions of the specificembodiments described herein are presented for purposes of illustrationand description. They are not targeted to be exhaustive or to limit theembodiments to the precise forms disclosed. It will be apparent to oneof ordinary skill in the art that many modifications and variations arepossible in view of the above teachings.

The advantages of the embodiments described are numerous. Differentaspects, embodiments or implementations can yield one or more of thefollowing advantages. Many features and advantages of the presentembodiments are apparent from the written description and, thus, it isintended by the appended claims to cover all such features andadvantages of the invention. Further, since numerous modifications andchanges will readily occur to those skilled in the art, the embodimentsshould not be limited to the exact construction and operation asillustrated and described. Hence, all suitable modifications andequivalents can be resorted to as falling within the scope of theinvention.

What is claimed is:
 1. A method to manage connections between a mobiledevice and a plurality of wireless networks, the method comprising: bythe mobile device: establishing a radio resource control (RRC)connection with a first wireless network; registering the mobile devicewith a second wireless network; sending to the first wireless network aradio resource suspension trigger that provides an indication to thefirst wireless network to suspend allocation of radio resources to themobile device; tuning one or more receivers of the mobile device tolisten for a page addressed to the mobile device from the second networkduring a suspension time period; and when not receiving a page addressedto the mobile device during the suspension time period and thesuspension time period does not exceed a time interval that results inthe first wireless network dropping the RRC connection: tuning the oneor more receivers of the mobile device back to the first wirelessnetwork, and sending a signaling message to the first wireless networkthrough the RRC connection, the signaling message providing anindication to the first wireless network that the mobile device is readyto resume data communication with the first wireless network.
 2. Themethod of claim 1, wherein the radio resource suspension triggercomprises a predefined combination of values for one or more of: achannel quality indicator, a precoding matrix indicator, or a rankindicator.
 3. The method of claim 1, wherein the radio resourcesuspension trigger does not comprise an extended service request (ESR)message that requests release of the RRC connection.
 4. The method ofclaim 1, further comprising: by the mobile device: when receiving a pageaddressed to the mobile device during the suspension time period:sending an extended service request (ESR) message to the first wirelessnetwork requesting release of the RRC connection; and sending a pageresponse message to the second wireless network.
 5. The method of claim4, further comprising: establishing a mobile terminated connection withthe second wireless network to support a voice call; and after the voicecall completes: tuning the one or more receivers back to the firstwireless network; and re-establishing another RRC connection with thefirst wireless network.
 6. The method of claim 4, wherein the mobiledevice sends the ESR message to the first wireless network beforesending the page response message to the second wireless network.
 7. Themethod of claim 4, wherein the mobile device sends the page responsemessage to the second wireless network before sending the ESR message tothe first wireless network.
 8. The method of claim 7, furthercomprising: by the mobile device: sending the ESR message to the firstwireless network after receiving an extended channel assignment from thesecond wireless network and before a traffic exchange with the secondwireless network begins.
 9. The method of claim 1, further comprising:when the suspension time period exceeds the time interval that resultsin the first wireless network dropping the RRC connection during thesuspension time period, re-establishing another RRC connection with thefirst wireless network.
 10. The method of claim 1, wherein: the firstwireless network comprises a long term evolution (LTE) wireless network,and the second wireless network comprises a CDMA2000 1× wirelessnetwork.
 11. A method to manage connection with a user equipment (UE)configured to communicate with a plurality of wireless networks, themethod comprising: by a radio access subsystem of a first wirelessnetwork: when the UE is associated with the first wireless networkthrough an established radio resource control (RRC) connection andsimultaneously registered with a second wireless network: receiving fromthe UE a radio resource suspension trigger that provides an indicationto suspend allocation of radio resources to the UE without dropping theestablished RRC connection; suspending allocation of radio resources tothe UE during a suspension time period; allocating radio resources toone or more other UEs during the suspension time period; and when thesuspension time period does not exceed a time interval that results indropping the established RRC connection, resuming allocation of radioresources to the UE after receiving a signaling message from the UEthrough the established RRC connection.
 12. The method of claim 11,wherein the resource suspension trigger comprises a predefinedcombination of values for one or more of: a channel quality indicator, aprecoding matrix indicator, or a rank indicator.
 13. The method of claim12, further comprising: by the radio access subsystem of the firstwireless network: re-establishing a new RRC connection between the UEand the first wireless network in response to receiving a request fromthe UE to re-establish another RRC connection.
 14. The method of claim11, wherein the radio resource suspension trigger does not comprise anextended service request (ESR) message that requests releases of the RRCconnection.
 15. The method of claim 11, further comprising: by the radioaccess subsystem of the first wireless network: when the suspension timeperiod exceeds an inactivity timer expiration time interval, releasingthe established RRC connection between the UE and the first wirelessnetwork.
 16. The method of claim 11, wherein the suspension time periodcomprises one or more paging cycles of the second wireless network. 17.The method of claim 11, wherein: the first wireless network comprises along term evolution (LTE) wireless network, and the second wirelessnetwork comprises a CDMA2000 1× wireless network.
 18. A non-transitorymachine-readable medium storing executable instructions that, whenexecuted by one or more processors of a mobile device, cause the mobiledevice to: establish a radio resource control (RRC) connection with afirst wireless network; register the mobile device with a secondwireless network; send to the first wireless network a radio resourcesuspension trigger that provides an indication to the first wirelessnetwork to suspend allocation of radio resources to the mobile device;tune one or more receivers of the mobile device to the second wirelessnetwork to listen for paging messages; and when not receiving a pageaddressed to the mobile device during a suspension time period: tune theone or more receivers of the mobile device back to the first wirelessnetwork; and resume communication with the first wireless network. 19.The non-transitory machine-readable medium of claim 18, wherein thesuspension time period does not exceed an RRC inactivity timerexpiration time interval.
 20. The non-transitory machine-readable mediumof claim 19, wherein execution of the instructions by the one or moreprocessors of the mobile device further causes the mobile device to:when not receiving the page addressed to the mobile device during thesuspension time period, send to the first wireless network a signalingmessage that provides an indication to the first wireless network toresume communication with the mobile device.